/***
 * ASM Guide
 * Copyright (c) 2007 Eric Bruneton, 2011 Google
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */

package cn.zwy.tree.day1;

import java.io.PrintWriter;
import java.util.Iterator;

import org.objectweb.asm.Opcodes;
import org.objectweb.asm.tree.ClassNode;
import org.objectweb.asm.tree.FieldNode;
import org.objectweb.asm.tree.MethodNode;
import org.objectweb.asm.util.TraceClassVisitor;

/**
 * ASM Guide example class.
 * 
 * @author Eric Bruneton
 */
public class RemoveMethodTransformer extends ClassTransformer implements Opcodes {

    private String methodName;

    private String methodDesc;

    public RemoveMethodTransformer(ClassTransformer ct, String methodName, String methodDesc) {
        super(ct);
        this.methodName = methodName;
        this.methodDesc = methodDesc;
    }

    public void transform(ClassNode cn) {
        Iterator<MethodNode> i = cn.methods.iterator();
        while (i.hasNext()) {
            MethodNode mn = i.next();
            if (methodName.equals(mn.name) && methodDesc.equals(mn.desc)) {
                i.remove();
            }
        }
        super.transform(cn);
    }

    public static void main(String[] args) {
        // 这样写代码可是比之前的代码爽多了 ， 效率肯定没有之前好
        ClassNode cn = new ClassNode();
        cn.version = V1_5;
        cn.access = ACC_PUBLIC + ACC_ABSTRACT + ACC_INTERFACE;
        cn.name = "pkg/Comparable";
        cn.superName = "java/lang/Object";
        cn.interfaces.add("pkg/Mesurable");
        cn.fields.add(new FieldNode(ACC_PUBLIC + ACC_FINAL + ACC_STATIC, "LESS", "I", null, new Integer(-1)));
        cn.fields.add(new FieldNode(ACC_PUBLIC + ACC_FINAL + ACC_STATIC, "EQUAL", "I", null, new Integer(0)));
        cn.fields.add(new FieldNode(ACC_PUBLIC + ACC_FINAL + ACC_STATIC, "GREATER", "I", null, new Integer(1)));
        cn.methods.add(new MethodNode(ACC_PUBLIC + ACC_ABSTRACT, "compareTo", "(Ljava/lang/Object;)I", null, null));
        TraceClassVisitor classVisitor = new TraceClassVisitor(new PrintWriter(System.out));
        //删除方法是需要遍历的
        ClassTransformer classTransformer = new RemoveMethodTransformer(null, "compareTo", "(Ljava/lang/Object;)I");
        classTransformer.transform(cn);
        cn.accept(classVisitor);
    }
}
